The rat, or other unidentified rodent, somehow got into an underground substation that serves north and northwest downtown, Ross said.

The power outage, which lasted from about 4:35 a.m. to 7:05 a.m., affected 15 to 20 buildings, including the Houston Chronicle's headquarters at 801 Texas Ave. The affected area was a block bounded by Preston on the north, Austin on the east, Walker on the south and Smith on the west, Ross said.

Given the early hour during what might be the year's slowest week, the outage created relatively little havoc.

The outage was felt at Jones Hall for the Performing Arts, 615 Louisiana, and the Post Rice Lofts parking garage at Travis and Prairie Streets but did not affect JPMorgan Chase Tower, 600 Travis, or the JPMorgan Chase Center across the street at 601 Travis.

While the image of a small animal stopping a stream of international commerce in its tracks is mind-boggling, it happens from time to time.

In June 2007, a raccoon, perhaps tempted by a nest of bird eggs, lost its life when it climbed into CenterPoint's Gable Street substation.

That outage affected about 1,500 customers for two hours, CenterPoint said at the time.

In the 2007 incident, CenterPoint said it had installed various deterrents, including high-frequency emitters near substations and some transformers to scare birds. These measures had helped reduce animal-caused outages by 75 percent in the previous 12 years, the company said.